Document ES-A-1015076 discloses a magnetic motor comprising two rotors assembled in a frame to rotate about respective parallel shafts. Identical and mutually meshing gear wheels are fixed to both shafts forcing the two rotors to rotate at equal speeds in opposite directions. Each rotor has cross-shaped arms at the ends of which permanent magnets are arranged. The magnets assembled in one of the rotors are fixed whereas the magnets assembled in the other rotor can rotate freely about respective shafts perpendicular to the shaft of rotation of the corresponding rotor.
Patent JP-A-60226766 describes a drive power generating device comprising a stator made up of an odd number of fixed permanent magnets arranged in pairs spaced at equal angular intervals around its inner perimeter, the magnets of each pair having opposite poles on their inner side, and a rotor assembled to rotate about an shaft and provided with an even number of permanent magnets spaced at equal angular intervals around its outer perimeter, all the magnets of the rotor having the same pole on the outer side. The device further comprises a magnetic unit capable of canceling the lines of magnetic force arranged between the stator and the rotor and mechanically connected to rotate in cooperation with the rotor. This magnetic unit controls the forces of repulsion and attraction between the permanent magnets of the stator and the rotor.
The patent JP-A-6137261 discloses rotating equipment comprising a number of fixed permanent magnets at equal angular intervals on the inner perimeter of a stator and an equal number of fixed permanent magnets at equal angular intervals on the outer perimeter of a rotor assembled to rotate about a shaft. A magnetic screen body with a portion of screen associated with each permanent magnet of the stator is statically arranged between the permanent magnets of the rotor and of the stator to interrupt lines of magnetic braking force at the time that they are the strongest.
Patent JP-A-58206884 describes a magnetic drive apparatus based on a first static permanent magnet arranged facing a second permanent magnet provided with vertical reciprocating movement and connected to a rotating shaft by means of a connecting rod and crankshaft mechanism. A device driven by an electromagnet arranges a screen plate between the two electromagnets and alternately removes it. When the screen plate is removed, the force of attraction between the two magnets displaces the second magnet upwards, performing half a turn of the shaft by means of the connecting rod and crankshaft mechanism. When the screen plate is arranged therebetween, the lines of force between the two magnets are interrupted and the second magnet moves down due to the effect of gravity, performing another half turn of the rotating shaft, and so on and so forth.
Documents ES-A-1048979, ES-A-1051230, CN-A-1078078, KR-A-100292857, KR-A-20010026946, KR-A-20010074126 and KR-A-20030009246 describe other examples of motor devices based on using the magnetic force exerted by permanent magnets.
In several of the aforementioned documents, the use of magnetic screens to interrupt or mitigate the interaction between the magnetic fields of permanent magnets is referred to. However, they do not mention the constructive features of such magnetic screens. A material in the art which allows building a relatively thin screen capable of interrupting the lines of magnetic force between two magnets or between a magnet and a ferromagnetic material is unknown.